Abstract: Steam-electric plants, nuclear of fossil fueled, are expected to provide the bulk of the growing needs for electric energy. As part of the operating cycle, such plants require large flows of water through the condensers to convert the exhaust steam to water. The condenser cooling water absorbs large amounts of waste heat which must be dissipated in some manner. The types of cooling systems in used include once-through, cooling ponds, and cooling towers of either mechanical or natural draft design. Cooling towers are sued where water supplies are limited or water quality standards prevent used of streams or lakes for waste heat disposal. Cooling towers add to power costs and are aesthetically undesirable. The addition of heat to water bodies may produce adverse effects on aquatic organisms. Although substantial studies have been completed or are under way, additional research is needed on the waste heat disposal problem. Areas of necessary research include the biological effects, the transport and behavior of heat in water, improved methods of cooling, and means of making beneficial use of waste heat.